Are you dosing calcium?? If you are, stop now. If you don't have a test kit, don't supplement.
Ca is used by corals. If you don't have any corals, you really don't need to worry about your levels. They should stay pretty level with routine water changes. You control Alk the same way. Regular water changes should keep everything in check. Good rule of thumb...if your pH is steady, most likely your Ca and Alk are steady as well.